Using their NHS number or by verifying their identity, vaccine-eligible users can book appointments for their Covid jab. However, it turned out there is currently no safeguard built into the site to protect against a person’s confidential vaccination status being disclosed to anyone with basic personal information about them.

This means that bosses, for example, can potentially keep tabs on whether, and which of, their employees had been vaccinated using just their names, dates of birth, and postcodes.

The problem lies in the fact that the site offers users different responses based on their vaccine status when they input personal information. For those yet to get a shot, entering their details lands them on a standard screening page, while those who have received one jab and booked their second are taken to a screen which requests their booking reference to manage appointments.

For users who have received both shots, inputting basic personal details sends them to a page which confirms they “have had both of [their] appointments.” Alarmingly, people who have received one shot through their GP can book their second with no additional verification required.

Noting that NHS Digital – the health service’s IT partner – was revising the pages, a spokesperson told the Guardian, “The system does not have any direct access to anyone’s medical record and people should not be fraudulently using the service – it should only be used by people booking their own vaccines or for someone who has knowingly provided their details for this purpose.”

In a series of tweets, privacy watchdog Big Brother Watch warned that the system left vaccination statuses “exposed for absolutely anyone to pry into,” and added that the “personal health information could easily be exploited by insurers, employers or scammers.”

“This is a seriously shocking failure to protect patients’ medical confidentiality at a time when it could not be more important,” the group’s director, Silkie Carlo, said in a statement, noting that date of birth and postcode “are fields of data that can be easily found or bought, even on the electoral roll.”

Carlo called for the immediate institution of “robust protections” and an “urgent investigation” into “how basic privacy protections could be missing from one of the most sensitive health databases in the country.”

A spokesperson for the National Data Guardian (NDG), which works with the Department of Health and Social Care to regulate the use of healthcare data, echoed those concerns to the Guardian, saying that the website had been developed to be as “simple and easy as possible” to use.

They said the NDG has contacted the organisations which run the website “to ensure that they are aware of the concerns that have been raised and will discuss with them the twin important aims of protecting confidentiality whilst maintaining easy access to vaccinations for the public.”

Expectedly, the reaction from Brits on social media was not as forgiving. A number of users questioned the NHS’ “complacence” and “naivete” in simply asking the public not to “fraudulently” use the site.